Many devices are known for facilitating exercises done for therapy, conditioning or physical training. Other than variable resistance training equipment, these devices have not usually offered much adjustability to allow for exercises at different degrees of difficulty. Also, many of these devices have been dedicated to very specific exercises and therefore do not justify a significant investment of space and financial resources for such a narrow purpose.
Some exercise devices require a person to maintain balance and equilibrium. A large inflatable ball (for example, 65 cm) known as a Swiss ball, has been used for this purpose. While the ball is useful for certain stability training exercises, standing upon the ball or staying atop the ball requires a high degree of skill and is inappropriate for most.
In U.S. Pat. No. 4,801,140 a person suffering from a physical disability can stand on the flat side of a non-inflatable molded foam hemisphere to practice balancing. The practical disadvantage of this design is that a high degree of skill is required before someone can actually stand on such an unstable platform. Without assistance from a therapist or additional balancing accessories, this platform is accessible only to trained athletes.
In U.S. Pat. No. 5,810,703 the underside of a small board is fitted with a smaller spherical projection. The relatively small diameter of the spherical projection tends to make the board relatively unstable. The height of the spherical projection can be set to one of three discrete settings. Overall, the adjustment has little range and resolution. Also, the projection, if inverted to face upwardly, is too small to allow a person to perform an exercise while placing weight on the projection.
An inflated cushion in the shape of a disk (sold under the name DuraDisk through C.H.E.K. Institute) has been described as useful for certain exercises. This cushion is described as needing no inflation, but the product is shipped with an inflation valve that the user has access to. A separate wooden platform, 20 inches in diameter, is sold for the purpose of placing the platform over the cushion to create a balance board. This cushion is relatively flat and therefore offers little challenge to a user. It is not useful for the inflatable disk to be placed on the board as this would offer no advantage over putting the inflatable disk on the floor. Also, the use of a separate platform requires careful placement and centering of the platform and also introduces the need for regularly finding and associating the separate parts.
In U.S. Pat. No. 5,643,154, a relatively squat, rounded ballast is mounted under a relatively wide platform. If the user is willing to stock an inventory, the rounded ballast can be changed, but the individual ballasts are not adjustable. This device is designed for use on land or in water. For use in water, an edge bumper is inflated an adjustable amount to reach the desired buoyance. While this edge bumper is adjustable, this adjustment is only effective in water. The stability of the platform on land will not be substantially affected by adjusting an edge bumper, which inherently provides a stable base. See also U.S. Pat. No. 3,024,021 for a non-adjustable device employing a platform connected through a resilient member to a rounded base.
U.S. Pat. No. 5,643,165 shows a frustroconical balancing device with a flattened apex. This device is stable in only one central position, and becomes highly unstable once titled slightly. Furthermore, the stability of this device is not adjustable. See also U.S. Pat. No. 5,549,536 for a continually tilted platform.
Accordingly, there is a need for an improved device that offers a unique experience and range of possible exercises, and that can allow adjustment, preferably with an inflatable device, to accommodate persons with different levels of skill and capabilities.